National Aquarium - The greater blue-ringed octopus is only about 4 inches across, but it holds enough venom to kill as many as 26 people... within minutes. Look, but definitely don't touch.
![Louise Cantillon on Twitter: "Sydney Living Tip #1 do not randomly pick up nice shells that have blue ringed octopus inside - thanks to my 9 and 10 year old sons who Louise Cantillon on Twitter: "Sydney Living Tip #1 do not randomly pick up nice shells that have blue ringed octopus inside - thanks to my 9 and 10 year old sons who](https://pbs.twimg.com/media/FmoA8gmaMAAdul2.jpg)
Louise Cantillon on Twitter: "Sydney Living Tip #1 do not randomly pick up nice shells that have blue ringed octopus inside - thanks to my 9 and 10 year old sons who
![Blue-ringed octopus, one of the most toxic animals on Earth, bites woman multiple times | Live Science Blue-ringed octopus, one of the most toxic animals on Earth, bites woman multiple times | Live Science](https://cdn.mos.cms.futurecdn.net/WfpsHvmJSw2YUAGCE2VKNT.jpg)